Automatic water-flow control for air compressors



March 13, 1945. MoN oE ETAL AUTOMATIC WATERFLOW CONTROL FOR AIRCOMPRESSORS Filed Sept. 2, 194? 311091430 4. RULLU EMUNEUE M WAL TEE ECLAPTUNJE 73mm a; 744

Patented Mar. 13, 1945 UNITED STATES PATENT OFFICE AUTOMATIC WATER-FLOWCONTROL FOR AIR COMPRESSORS Rollo 0. Monroe and Walter F. Clayton, J12,Three Rivers, 'Mich., assignors to The Johnson Corporation, ThreeRivers, Mich., a corporation of Michigan Application September 2, 1942,Serial No. 457,056

6 Claims.

1 of the compressor without cooling water followed by undesirableconsequences,

.-The present invention overcomes the difiiculties of the prior art byproviding the controlling system wherein in the event of the failure ofwater to flow for any reason whatsoever, the compressor is stopped.Furthermore, according to the present invention, the compressor cannotbe started without the circulation of cooling water.

An object of the present invention is to provide a control for thecooling water of a compressor, or the like.

Another object of the invention is to coordinate the flow of coolingwater with the operation of the compressor.

Still another object of the invention is to provide compressor operatingand water controlling electrical circuits and to coordinate theoperation of the circuits. r

A still further object of the invention is to providethe cooling wateritself as a part of a compressor operating circuit.

1 These and other objects residing in the arrangement, combination andconstruction of the parts will be apparent from the followingspecification when taken with the accompanying drawing, in which I Fig.1 diagrammatically represents a compressor system according to thepresent invention, and

Fig. 2 is a wiring diagram of the electrical circuit employed, in, butnot disclosed in, the system of Fig. 1. I

Referring particularly to the drawing, the reference character Iindicates a compressor driven by a motor 2 through a belt 3. Compressedair provided by, the compressor is conducted through a .conduit 4 to anafter cooler 5 and from the after cooler 5 is conducted through aconduit 8, to a separator l. A conduit 8 conducts the compressed air toan air receiver 9. Compressed air from the air receiver. 9 is conductedtherefrom by a service conduit ID to thepoints of use.

The separator "I is provided with an outlet conduit II in which isdisposed a trap I2 having a conduit I3 connected thereto providing aconnection with a drain not shown. The air receiver 9 is. provided witha relief valve l4, and a pressure responsive switch I5 for controllingthe operation of the compressor I and the flow of cooling water as willbe hereinafter described.

Cooling water for the compressor is conducted from a source, not shown,through a conduit 20, a valve 2|, a solenoid valve 22, a valve 23, aconduit 24, a fitting and a conduit 26 to the after cooler 5. Thesolenoid valve 22 is by-passed by a conduit 21 having a valve 28therein. An electrode 29 is disposed in the fitting 25 as shownparticularly in Fig. 2. Cooling water from th after cooler 5 isconducted by a conduit 29 to the water jacket of the compressor I andfrom the compressor I to a drain conduit 30. I

. The operation of the invention can best be understood by referencetothe wiring diagram disclosed in Fig. 2. The electric motor 2 is drivenby electric current carried through conductors 32 from a suitable sourcethrough a switch 33 and a starter 34. The conductors 32 are connected tothe motor 2 through the switch 33 and the starter 34'by conductors 35. Aconductor 36 is connected to one of the conductors 32 through theprimary of atransformer 31 to a conductor 38 and the conductor 38 isconnected to another one of the conductors 32. In series with theconductors 36 and 38 and the primary of the transformer 31 is thepressure responsive switch [5 actuatedby a pressure responsive device40. In parallel with the primary of the transformer 31 across the mallyclosed but upon being electrically energized it is opened to permit theflow of cooling water.

The secondary of the transformer 31 has one end thereof grounded and theother end connected in series with the actuating coil of a relay switch43 and the electrode 29 of the fitting 25, by a conductor 44. The relayswitch 43 is arranged in a. circuit consisting of the conductor 38including the pressure responsive switch I5 and a conductor 45 includingthe relay switch 43, connected at one end to the conductor 38 and at theother end to one end of the solenoid 0011.46 ofithe,

- pressor I.

motor starter 34. The opposite end of the coil 46 is connected to theconductor 32 which is con- ,nected to the conductor 36.

The operation of the device is as follows: Assume that the compressor Ihas operated and built up a pressure in the air receiver 9 and then hasstopped. At this stage there will be no flow of cooling water. Assumethen that the pressure in the air receiver 9 drops due to use so thatthe pressure responsive device 40 is actuated to close the switch l5. Acircuit is then closed including the conductor 35, the solenoid valve22, the conductor 38 and the switch 15. The closing of this circuitopens the solenoid valve 22 to start the flow of cooling water. As soonas the cooling water passing through the conduit 24 strikes theelectrode 29, a, circuit is closed through the ground including thesecondary of the transformer 31, the conductor 44 and the coil of therelay switch 43. The closing of the relay switch 43'closes the circuitincluding the conductor 38 which includes the previously closed pressureresponsive switch IS, the conductor 45 and the coil 46 of the motorstarter 34. The closing of this circuit closes the motor starter tostart the compressor motor 2 and thus the com- Should the pressure inthe air receiver 9 rise to such a" point that the pressure responsiveswitch I is opened, the solenoid valve 22 is closed by the opening ofits circuit and also the motor starter 34 circuit including theconductors 38, 45, the relay switch 43 and the coil 46 is opened to stopthe motor and thus the compressor.

In analyzing the operation of the system according to the presentinvention, it will be clear that the motor 2 for the compressor I cannotoperate until the cooling water starts to flow and completes the circuitof the motor starter 34 through the relay switch 43. Thus, it is theflow of cooling water that is responsible for the starting of the motor2. The fitting 25 is placed at a high point of the water system so thatshould the How of cooling water fail, due to some accidental,purposeful, or other cause, the water will gravitate away from theelectrode 29', opening the relay switch 43 circuit and the relay switch43', to open the motor starter 34.circuit' which includes the conductor38, the conductor 45, and the coil 46'. The operation which the presentinvention provides has a very definite safety feature in that thecompressor cannot operate until the cooling water is flowing and has aneconomy feature that the cooling water does not flow when the compressoris not operating.

While the invention has been described particularly with respect to acompressor for storing compressed air, it will be understood that theinvention has other applications as ior instance in compresscrs'forrefrigerating units or other installation where the flow of a conductingliquid is required. In the control of the cooling water for compressorsforrefrigerating units it will he understood that it is not necessarythat a pressure actuate the switch for controlling the solenoid valveoperation as some other varying condition may be employed toclose thiscircuit. Furthermore in compressor systems the use of an after coolerand separator for the compressed aiu are not a part of the invention andmay be omitted. In the claims it is contemplated that"water includeother conducting liquids of an equivalent nature.

Having thus described our invention, what we desire to secure by LettersPatent and. claim is:

1. A device for controlling the flow of a liquid for a liquid cooledcompressor, which comprises a liquid conduit system for conducting saidliquid from a source to said apparatus, a valve in said conduit system,pressure means responsive to pressure built up by said compressor foropening said valve to provide a flow of said liquid, starting means forsaid compressor, and means responsive to said flow of Water foractuating said starting means.

2. A device for controlling the flow of cooling water for a compressorwhich comprises a water conduit system for conducting water from asource to said compressor, a valve in said conduit system, a reservoirfor compressed air provided by said compressor, means responsive to apredetermined minimum pressure in said reservoir for opening said valveto provide a flow of said water, starting means for said compressor, andmeans responsive to said flow of water for actuating said startingmeans.

3. A device for controlling the flow of cooling water for a compressorwhich comprises a water conduit system for conducting water from asource to said compressor, anelectrically actuated valve in said conduitsystem, said valve being normally closed, a reservoir for compressed airprovided by said compressor, a circuit having means responsive to apredetermined low pressure in said reservoir to close said circuit toopen said valve upon said reservoir reaching a pre--v determined lowpressure and for closing said valve upon said'reser'voir reaching apredeter-- mined high pressure, and a, second circuit having means toclose the same upon the flowing of said water, to start said compressorand to open the same to stop said compressor upon the stop-- ping of theflow of said water.

4. The invention as defined in claim 3 wherein the means to closethe'second circuit includes a third circuit closable through said waterto the ground.

5. The invention as defined in claim 3 wherein the pressure responsivecircuit closing means is in both the first and second circuits.

6. A device for controlling the flow of cooling water for a compressorwhich comprises a water conduit system for conducting water from asource to said compressor, an electrically controlled valve in saidconduit system, anelectric circuit for controlling. the operation ofsaid valve, a switch for opening and closing said circuit, a reservoirfor storing compressed air providedby said compressor, means responsiveto a predetermined low pressure in said reservoir to close said switchand responsive to a predetermined high pressure in said reservoir toopen said switch, closing said circuit to open said valve toprovide aflow of said water and the opening of said switch opening said circuitto close said valve to stop the flow of said water, an electricallycontrolled starting means for said apparatus, an electric circuitincluding the first named switch for controlling said starting means, asecond switch in said last named circuit, a third circuit for closingsaid second named switch, and means responsive to the flow of waterin'said conduit system for closing said third circuit for closing saidsecond circuit for actuating said starting means to start saidcompressor, whereby either the opening of said third circuit orof saidpressure responsive switch will stop said com-

